I can't believe it's that old! This is the best recording of the sonata I've ever heard - so many tasteful interpretations, melodic improvisations from the lute and harpsichord. Although, I think I can hear a guitar in the 16th section? Then we have the final variations, ever since I heard them I've always wondered what articulation they are using??? The madness has really reached its pinnacle here, and I absolutely love it.
Yeah! Follia was a 15th century folk tune from Iberian Peninsula (some say from Portugal, others that from north of Spain), and later it became popularised in European courts, especially in Italy and France, so a lot of composers made variations over the original tune, for example Marin Marais, Arcangelo Corelli or Antonio Salieri. Even Bach has one in a cantata! Later there are a few more follias in Beethoven or in Rachmaninov. Hope I've helped you!😄